Discrete particle simulation of bubble and slug formation in a two-dimensional gas-fluidised bed: A hard-sphere approach
Discrete particle simulation of bubble and slug formation in a two-dimensional gas-fluidised bed: A hard-sphere approach
复制标题
DOI：
10.1016/0009-2509(95)00271-5
复制
发表时间：
1996-01-01
影响因子：
4.7
通讯作者：
vanSwaaij, WPM
中科院分区：
文献类型：
--
作者：
Hoomans, BPB;Kuipers, JAM;vanSwaaij, WPM
已经建立了一个气体流化床的离散粒子模型，在这个模型中，单个球形粒子的二维运动是直接从作用在它们身上的力计算出来的，考虑了粒子和间隙气相之间的相互作用。我们的碰撞模型基于线动量和角动量守恒定律，除了几何因素外，还需要两个经验参数：恢复系数和摩擦系数。用在分子动力学领域中经常遇到的硬球模拟中应用的技术处理了一系列碰撞。气相的流体动力学模型是基于体积平均的Navier-Stokes方程。在一个小的二维床（高0.50 m，宽0.15 m）中，2400个颗粒(d（p) = 4 mm，材料：铝，rho = 2700 kg m(-3)）的气泡和段塞形成的模拟表明，在恢复和摩擦系数方面，如何行为具有很强的依赖性。采用小型“二维”气体流化床（高0.30 m，宽0.15 m，深0.015 m），以850 μ m气球玻璃颗粒（rho = 2930 kg m(-3)）为床料，对我们的模型进行了初步实验验证。结果与使用简单独立实验获得的真实恢复系数和摩擦系数的40,000个粒子的模拟结果相当吻合。
A discrete particle model of a gas-fluidised bed has been developed and in this the two-dimensional motion of the individual, spherical particles was directly calculated from the forces acting on them, accounting for the interaction between the particles and the interstitial gas phase. Our collision model is based on conservation laws for linear and angular momentum and requires, apart from geometrical factors, two empirical parameters: a restitution coefficient and a friction coefficient. A sequence of collisions is processed using techniques which find their application in hard-sphere simulations which are commonly encountered in the field of molecular dynamics. The hydrodynamic model of the gas phase is based on the volume-averaged Navier-Stokes equations. Simulations of bubble and slug formation in a small two-dimensional bed (height 0.50 m, width 0.15 m) with 2400 particles (d(p) = 4 mm, material: aluminium, rho = 2700 kg m(-3)) showed a strong dependency of the how behaviour with respect to the restitution and friction coefficient. A preliminary experimental validation of our model was performed using a small scale ''two-dimensional'' gas-fluidised bed (height 0.30 m, width 0.15 m, depth 0.015 m) with 850 mu m ballotini glass particles (rho = 2930 kg m(-3)) as the bed material. Results compared fairly well with the results of a simulation which was performed with 40,000 particles using realistic values for the restitution and friction coefficients which were obtained from simple independent experiments.